“It’s appalling and no provisions are being made for these people – they’re just expected to conform.”

Figures obtained by the Reporter Series reveal ambulances were involved in nearly 400 crashes while responding to 999 calls and almost 200 bumps in hospital car parks and ambulance stations.

But the trust insisted the number of crashes was decreasing and its drivers were given advanced training to prevent accidents.

Associate director of support services Mark Squires said: “The trust’s fleet of over 1,000 emergency and non-emergency vehicles cover more than 30 million miles every year and this mileage is increasing as the service becomes busier.

“Our staff receive comprehensive driver training and for those working in our emergency service this also includes blue-light training.

“The number of vehicle-related incidents recorded annually is decreasing and we are committed to reducing this further.”

YAS worker Mark Burt is a health and safety rep for the union Unite.

He said: “It looks from the ground like there has been an increase in crashes.

“The trust doesn’t have enough qualified staff and regulators need to look at what is going on.”

Unite assistant general secretary Gail Cartmail said: “Unite has been inundated with concerns from patients and the public about the YAS.

“In three constituencies the union has visited in Yorkshire, a constant stream of concerns are already coming in.

“Staff must have the right to blow the whistle if they feel the service is gambling with patients’ lives.”

Unite , which has around 450 members within the service, was re-recognised by the trust to negotiate on behalf of its members this week after two years of bitter dispute.

Negotiations between the two sides effectively ended on February 9, 2013, when the ambulance service ceased to recognise the union.

The move to de-recognise Unite came after the union claimed patient safety was being put at risk by cost-cutting plans to allow semi-skilled care assistants to be sent out on 999 calls.